1. Field of the Invention
The invention relates to a current supply arrangement for supplying at least one load with electric energy from a source. The current supply arrangement includes a switching stage for optionally switching-on the load in accordance with a switching signal applied thereto and a control circuit which in its switched-off state cuts the supply of energy to the switching stage and to the load, and in its switched-on state controls the energy supply to at least the switching stage, the control circuit also receiving the switching signal for switching between the on and off states. The control circuit includes a start circuit by which the energy required for changing from the switched-off state to the switched-on state can be applied from the source to the control circuit, and which is made operative for the supply of energy to the control circuit by the switching signal. The current supply arrangement also includes a switching signal transmission device for transmitting the switching signal to the switching stage and the control circuit, the switching signal transmission device being supplied with the electrical energy required for its operation from the start circuit.
2. Description of Related Art
The VALVO data book "Integrierte Analogschaltungen fur Fernseh- and Videogerate" 1987, pages 285 to 294, describes a control circuit for a current supply arrangement in the form of a switched-mode power supply in color television sets, which is designed as a monolithically integrated circuit. In this control circuit, a what is commonly denoted a "stand-by mode" is provided, in which the control circuit drives a power supply switching transistor through which a current is periodically passed from a line voltage rectifier through a primary winding of a line transformer and consequently a supply voltage is generated on the secondary side of the line transformer, with which a microprocessor is supplied, which controls the function of the television set, more specifically the adjustment of the programs to be received and the adjustments for volume, brightness, etc. In what is commonly referred to as the "normal operation", also all the further circuit portions of the color television set are supplied with energy from the line transformer. They can be connected to the power supply by the microprocessor.
In the "stand-by mode" the picture display and sound reproduction of the television set are indeed switched-off by the microprocessor, but it remains itself in operation, to provide that it can switch on the television set again. This operating mode is used in television sets with remote control and in the "stand-by mode" also the remote control receiver in the television set is supplied with current, to enable it to switch the set on again at any moment via the remote control. Consequently, in the "stand-by-mode" the switched-mode power supply with the control circuit, the microprocessor and the remote control receiver remain continuously in operation and therefore require an electric power which is so high as not to be disregarded. In addition to current consumption costs, the set is heated unnecessarily and circuit sections not required are loaded by electric voltage, which means that there is a risk of damage to the set and also of electrical accidents to the operator.
German Patent DE No. 34 12 341 discloses a television set which is supplied from the 220 V main supply and includes an evaluation circuit 5 which switches the television set on, and a switched-mode power supply 12 having a "Stand-by I state", a "Stand-by II state" and a normal state. In this set a remote control signal amplifier applies pulses to the switched-mode power supply for adjusting it to the "Stand-by II state", and transfers the pulses to the evaluation circuit. The energy for the short switch-on interval of the set is supplied by an electrolytic capacitor of a power supply 4. The remote control signal amplifier is supplied with energy by the power supply 4.